Display attachment for sign



FIG. 1 is a front view of the design shown in its normal condition of use at the top of a sign;

FIG. 2 is an enlarged perspective view of the front of the design;

FIG. 3 is an end view of the design; and,

FIG. 4 is a top view of the design.

The broken lines in the drawings depict environmental structure, which forms no part of the claimed design. 

The ornamental design for a display attachment for sign, as shown. 